AS5040 8-bit Programmable Magnetic Rotary Encoder
AS5040/AS5045/AS5140/AS5145/AS5145-I10(-I12)
Programmable Magnetic Rotary Encoder
1 General Description
The AS5x40/AS5x45 series are contactless magnetic rotary encoders for accurate angular measurement over a full turn of 360°. They are system-on-chip, combining integrated Hall elements, analog front end and digital signal processing in a single device.
To measure the angle, only a simple two-pole magnet, rotating over the center of the chip, is required. The magnet may be placed above or below the IC.
The absolute angle measurement provides instant indication of the magnet’s angular position with a resolution of
0.35° = 1024 (AS5x40 – 10bit ) or 0.0879° = 4096 (AS5x45 –
12bit) positions per revolution. This digital data is available as a serial bit stream and as a PWM signal.
AS5040-AB-v2.0
Adapterboard
OPERATION MANUAL
Furthermore, a user-programmable incremental output is available, making the chip suitable for replacement of various optical encoders.
The AS5145 is also available as 10bit or 12bit preprogrammed version AS5145-I10(-I12).
An internal voltage regulator allows the AS5x40/AS5x45 to operate at either 3.3 V or 5 V supplies.
2 The AS5040 Adapter board
2.1
Board description
The AS5040 adapter board is a simple circuit allowing test and evaluation of the AS5040/AS5045/AS5140/AS5145/AS5145-
I10/AS5145-I12 rotary encoder quickly without building a test fixture or PCB.
The PCB can be used as standalone unit or attached to a microcontroller. The standalone operation requires a 5V power supply only; the magnet’s angle can be read on the PWM or analog output.
AS5x40/AS5x45 encoder
J1 connector
(Prg, power supply, serial interface)
J2 connector
(PWM, incremental and status outputs)
4 x 2.6mm mounting holes
Figure 1: AS5040 Adapter board
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Adapterboard Operation Manual
2.2
Mounting the AS5040 adapter board
Bearing
M2~M2.5 Screw + nut
Rotating shaft and magnet holder
Not ferromagnetic (plastic, brass, copper, stainless steel, aluminum…)
Casing
Spacer
AS5040-AB PCB
Figure 2: AS5040 adapter board mounting and dimension
A diametric magnet must be placed over on under the AS5x40/AS5x45 encoder, and should be centered on the middle of the package with a tolerance of 0.5mm.
The airgap between the magnet and the encoder casing should be maintained in the range 0.5mm~2mm.
The magnet holder must not be ferromagnetic. Materials as brass, copper, aluminum, stainless steel are the best choices to make this part.
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AS5040/AS5045/AS5140/AS5145/AS5145-Ix Programmable Magnetic Rotary Encoder
Adapterboard Operation Manual
3 AS5x40/AS5x45 and adapter board pinout
MagINCn
1
MagDECn
A_LSB_U
B_Dir_V
2
3
4
NC 5
Index_W
VSS
Prog
6
7
8
Figure 3: AS5040 adapter board connector s and encoder pinout
16
15
14
13
12
11
10
9
VDD5V
VDD3V3
NC
NC
PWM_LSB
CSn
CLK
DO
Pin#
Board
JP1 - 1
JP1 - 2
JP1 - 3
Pin#
AS5040
7
9
10
JP1 - 4
JP1 - 5
JP1 - 6
JP1 - 7
JP2 - 1
JP2 - 2
JP2 - 3
JP2 - 4
JP2 - 5
JP2 - 6
JP2 - 7
11
15
16
8
7
1
2
3
4
6
12
Symbol
Board
GND
DO
CLK
CSn
3V3
5V
P r r g
GND
MagINC
MagDEC
A
B
Ind
PWM
Type Description
S Supply ground
DO_T
Data Output of Synchronous Serial Interface
DI_ST
Clock Input of Synchronous Serial Interface; Schmitt-Trigger input
DI_PU_ST
Chip Select, active low; Schmitt-Trigger input, internal pull-up resistor (~50k
Ω
) connect to VSS in incremental mode
S
S
DI_PD
3V-Regulator Output
5V Supply
OTP Programming Input and Data Input for Daisy Chain mode. Internal pull-down resistor
(~74k
Ω
).
May be connected to VSS if programming is not used
S
DO_OD
DO_OD
DO
Supply ground
Magnet Field Magnitude INCrease; active low, indicates a distance reduction between the magnet and the device surface.
Magnet Field Magnitude DECrease; active low, indicates a distance increase between the device and the magnet
AS5040 – AS5140 – AS5145 (programmed) only
Mode1.x: Quadrature A channel
Mode2.x: Least Significant Bit
Mode3.x: U signal (phase1)
DO
DO
DO
AS5040 – AS5140 – AS5145 (programmed) only
Mode1.x: Quadrature B channel quarter period shift to channel A.
Mode2.x: Direction of Rotation
Mode3.x: V signal (phase2)
AS5040 – AS5140 – AS5145 (programmed) only
Mode1.x and Mode2.x : Index signal indicates the absolute zero position
Mode3.x: W signal (phase3)
AS5045 – AS5145 (unprogrammed)
Mode input, connect to VDD5 (Fast mode) or GND (Slow mode); do not change during
operation
Pulse Width Modulation of approx. 1kHz; LSB in Mode3.x
Table 1: Pin description
Pin types: DO_OD digital output open drain
DO digital output
DI_PD digital input pull-down
DI_PU digital input pull-up
S
DI
DO_T
ST supply pin digital input digital output / tri-state
Schmitt-Trigger input
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AS5040/AS5045/AS5140/AS5145/AS5145-Ix Programmable Magnetic Rotary Encoder
Adapterboard Operation Manual
4 Operation use cases
4.1
Standalone SSI output mode
4.2
Standalone PWM output mode
Figure 4: Using the analog output with the adapter board
The most complete and accurate solution for a MCU to read the angle of a magnet is the serial interface.
The serial word contains 16 bits for AS5x40 or 18 bits for
AS5x45 and consists of 10 bit (AS5x40) or 12 bit
(AS5x45) angle value and some other indicator bits like
MagINC, MagDEC, which can be read at the same time.
Figure 5: Using the PWM output with the adapter board
The AS5040 provides a pulse width modulated output
(PWM), whose duty cycle is proportional to the measured angle. The PWM signal (J2 pin #7) with a period of
1025us (1us step) and 5V pulse voltage can be connected to the capture/timer input of a microcontroller in order to decode the angle value.
Angle
PW
MIN
0 deg
(Pos 0)
1µs
102 5µs
PW
M AX
359.65 deg
(Pos 1023)
102 4µ s
Figure 6: PWM duty cycle depending on magnet position
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4.3
Standalone incremental output
Figure 7: Using the Incremental output with the adapter board
Three different incremental output modes are possible with quadrature A/B being the default mode (two-channel quadrature, step / direction incremental signal (LSB) and the direction bit in clockwise (CW) and counter-clockwise (CCW) direction.
The pre-programmed version AS5145-I10 provides a 10bit and AS5145-I12 a 12bit incremental output.
The AS5045 do not offer an incremental output (see chapter 6).
For further information, please refer to datasheet.
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AS5040/AS5045/AS5140/AS5145/AS5145-Ix Programmable Magnetic Rotary Encoder
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4.4
Daisy chain mode
Figure 8: Using Daisy-Chain mode with the adapter board
By using more than one adapter board, a setup in daisy chain mode is possible.
In this mode capacitor C3 (refer to Fig.10) must be disconnected when using the 1nF capacitor shown in Fig.8. or directly replaced by this capacitor.
The serial data of all connected devices is read from the DO pin of the first device in the chain. The Prog pin of the last device in the chain should be connected to VSS. The length of the serial bit stream increases with every connected device
(board) by n * (16+1) bits.
Due to R = 100R and C = 1nF, the CLK is limited the maximum 1MHz.
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AS5040/AS5045/AS5140/AS5145/AS5145-Ix Programmable Magnetic Rotary Encoder
Adapterboard Operation Manual
5 Programming the AS5040
Figure 9: Programming the AS5040
After power-on, programming the AS5040 is enabled with the rising edge of CSn with Prog = high and CLK = low. 16 bit configuration data must be serially shifted into the OTP register via the Prog-pin. The first “CCW” bit is followed by the zero position data (MSB first / 10 bit for AS5x40 and 12 bit for AS5x45) and some mode settings (please refer to datasheet). Data must be valid at the rising edge of CLK.
After writing data into the OTP register it can be permanently programmed by rising the Prog pin to the programming voltage
V
PROG of 7.3-7.5V. 16 CLK pulses must be applied to program the fuses.
For exiting the programming mode, the chip must be reset by a power-on-reset. The programmed data is available after the next power-up.
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6 AS5040 Differences to AS5045
Building Block
Resolution
Data length incremental encoder
Pins 1 and 2
Pin 6
Pin 12 sampling frequency
Propagation delay
Transition noise
(rms; 1sigma)
OTP programming options
AS5045
12bits, 0.088°/step. read: 18bits
(12bits data + 6 bits status)
OTP write: 18 bits
(12bits zero position + 6 bits mode selection)
Not used
Pin 3: not used
Pin 4:not used
MagINCn, MagDECn: same feature as AS5040, additional OTP option for red-yellow-green magnetic range
MODE pin, switch between fast and slow mode
PWM output: frequency selectable by OTP:
1µs / step, 4096 steps per revolution, f=244Hz
2µs/ step, 4096 steps per revolution, f=122Hz selectable by MODE input pin:
2.5kHz, 10kHz
384µs (slow mode)
96µs (fast mode)
0.03 degrees max. (slow mode)
0.06 degrees max. (fast mode) zero position, rotational direction, PWM disable, 2
Magnetic Field indicator modes, 2 PWM frequencies
AS5040
10bit, 0.35°/step read: 16bits
(10bits data + 6 bits status)
OTP write: 16 bits
(10bits zero position + 6 bits mode selection) quadrature, step/direction and BLDC motor commutation modes
Pin 3:incremental output A_LSB_U
Pin 4:incremental output B_DIR_V
MagINCn, MagDECn indicate in-range or out-of-range magnetic field plus movement of magnet in z-axis
Pin 6:Index output
PWM output:
1µs / step, 1024 steps per revolution,
976Hz PWM frequency fixed at 10kHz @10bit resolution
48µs
0.12 degrees zero position, rotational direction, incremental modes, index bit width
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7 AS5040 adapter board hardware
7.1
AS5040-AB-2.0 schematics
Figure 10: AS5040-AB-2.0 adapterboar d schematics
7.2
AS5040-AB-2.0 PCB layout
Figure 11: AS5040-AB-2.0 adapter board layout
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AS5040/AS5045/AS5140/AS5145/AS5145-Ix Programmable Magnetic Rotary Encoder
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Table of contents
1 General Description........................................................................................................................................................... 1
2 The AS5040 Adapter board............................................................................................................................................... 1
2.1
Board description ...................................................................................................................................................... 1
2.2
Mounting the AS5040 adapter board........................................................................................................................ 2
3 AS5x40/AS5x45 and adapter board pinout ....................................................................................................................... 3
4 Operation use cases.......................................................................................................................................................... 4
4.1
Standalone SSI output mode .................................................................................................................................... 4
4.2
Standalone PWM output mode ................................................................................................................................. 4
4.3
Standalone incremental output ................................................................................................................................. 5
Figure 7: Using the Incremental output with the adapter board ............................................................................................. 5
4.4
Daisy chain mode ..................................................................................................................................................... 6
5 Programming the AS5040 ................................................................................................................................................. 7
6 AS5040 Differences to AS5045......................................................................................................................................... 8
7 AS5040 adapter board hardware ...................................................................................................................................... 9
7.1
AS5040-AB-2.0 schematics ...................................................................................................................................... 9
7.2
AS5040-AB-2.0 PCB layout ...................................................................................................................................... 9
Table of contents...................................................................................................................................................................... 10
Copyrights ................................................................................................................................................................................ 11
Disclaimer................................................................................................................................................................................. 11
Contact Information .................................................................................................................................................................. 11
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AS5040/AS5045/AS5140/AS5145/AS5145-Ix Programmable Magnetic Rotary Encoder
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Copyrights
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AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application.
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